Orientalosuchina

Orientalosuchina is an extinct clade of alligatoroid crocodylians from Southeast and East Asia that lived from the Maastrichtian to the Eocene. Orientalosuchina are generally small in stature, with even the larger genera being described as "medium-sized" at most and possibly reaching a length of only around 2 m (6 ft 7 in). Members of the clade tend to have blunt, rounded snouts and more bulbous cheek teeth.

Though some members of the group have been known since the mid 20th century, the clade has only been recognized as such in 2019 and even then some authors have disputed the inclusion of certain taxa like Jiangxisuchus and Eoalligator. The exact relationship between orientalosuchins and other crocodylians has likewise been debated. They are conventionally regarded as a basal offshoot of Alligatoroidea, though some researchers have argued that they could be more closely related to crocodyloids or even mekosuchines. This confusion stems in part from the unique mix of anatomical features seen in members of the group, which combine the globular cheek teeth traditionally associated with alligatoroids with partially interlocking dentition as seen in crocodyloids.

The ecology of orientalosuchins has received little attention in literature. While it was once suggested that some of them may have been more terrestrial, it is now generally assumed that orientalosuchins were semi-aquatic. Their posterior teeth may suggest a more durophagous diet and fossils from the Na Duong Basin may be evidence of Orientalosuchus preying on turtles. By the Eocene orientalosuchins are known to have coexisted with the narrow-snouted and likely piscivorous gavialoid Maomingosuchus and at least in some regions with a large generalist crocodilian similar to Asiatosuchus. This suggests that the smaller orientalosuchins filled a different niche from these contemporary species.